In sales and credit card transactions, which are in extensive use today, the merchant is provided with an assembled pack of transaction slips for recording information relating to the merchant, the customer's credit card account number, etc. at defined positions on the slips. The pack may consist for example of a first paper transaction slip to be retained by the merchant, a second paper transaction slip to be given to the customer, and a third paper transaction slip which is forwarded to the bank or credit card issuer. One or more paper duplicating slips having a duplicating medium, commonly known as duplicating carbon slips, are included in the pack, with at least one duplicating carbon slip sandwiched between two transaction slips.
In normal use a sales clerk records the transaction information on the top transaction slip in the pack and may also at the same time imprint information onto all of the transaction slips as enabled by the intermediate duplicating carbon slips. The respective transaction slips are then deleaved or disjoined from the pack for presentment to the customer and the remaining duplicating carbon slips are placed into a container for later disposal.
The transaction slip(s) retained by the merchant may be used to computerize information about the customer, such as frequency of buying and current address. Another important use of this information can be to create a mailing list for advertising. If this information is intercepted by unauthorized personnel, it may lead to a loss of business.
Additionally, it has been found that in some instances certain individuals have obtained the customer's identifying account number from a used duplicating carbon slip and wrongfully utilized this information. Several methods have been utilized to attempt to prevent this unauthorized use. Prior methods include the use of expensive non-carbon duplicating forms, tearing or shredding of the carbon slips, and perforating lines on the carbon slips as can be seen in U.S. Pat. No. 4,403,793 to J. A. McCormick, et al. These methods have, however, proven to be either expensive, dirty, or unable to obscure multiple lines of information.
It is, therefore, the object of this invention to provide a cheap and clean way to effectively obscure multiple lines of information on credit slip carbons.